Propeller blade



' Nov.l 11, 1941,

c. H. BRAUCHLER PROPELLER BLADE Filed May 25, 1959 2 Sheets-Sheet 1 f iig-U gmc/wm i Nov. 11, 1941. c, H. BRAU'CHLER i 2,262,163

PROPELLER BLADE Filed May 25, 1939 2 Sheets-Sheet? -Patented Nov. 1l, 1941 UNITE-,D STATES] y PATENT OFFICE l POPLADE Chandis il'. Brauchler, Canton, Ohio Application May 25, 1939, Serial No. 275,633

(ci. 17o- 159) '4 claims.

and have been found vto be stronger-'than'the solid blades of duralumin and similar light weight metals and alloys, while at the same time beingdighter in weight.

Owing to the considerable vibration set up in such propeller blades when in operation the present invention contemplates a reinforced hollow metal blade so constructed that it will strengthen the blade without materially adding to the weight thereof.

This may be accomplished by locating ametal tube within the hub portion of the blade and tapered toward the tip thereof forming a central longitudinally disposed reinforcing tube through the blade. ,Y

The edge portions of the hollow blade may be further reinforced by locating smaller metal tubes within the tubular blade adjacent to the edge portions thereof.

Another object of the invention-is the method by which the improved reinforced hollow blade is made. l

The invention may be accomplished in the manner hereinafter described and illustrated in the accompanying drawings in which l Figure 'l is a longitudinal sectional view through a tubular blank for forming a hollow metal blade with the reinforcing tubes pressed therein;

Fig. 2, a similar view of the partly completed product after the same has beenI pressed or forged to the4 desired cross-sectional shape;

Fig. 3, an elevation of the completed blade; and

Figs. 4 to 16, inclusive, are transverse sectional views taken on the lines 4-'4 to it-IB, inclusive,v

it will be of proper cross-sectional shape from the hub end to substantially the middlev portion of the blade.

For the purpose of reinforcing the blade, a smaller tube 23, tapered from one end toward-the other, and of proper diameter at its larger end to snugly t within the hub end portion 2| of the blank shown in Fig. 1, as indicated at 2l, is

inserted into the tube blank 20 and the larger end thereof may be welded within the hub portion 2l of said tube blank with the smaller end Fig. 3, showing the cross-sectional shapes of the l completed blade at spaced intervals from the hu and to the tip end of the blade.

Similar numerals refer to similar parts throughout the several views.

In making the improved propeller blade a metal tube 20, preferably a seamless steel tube, is'

reduced to the desired iinishedvdiameter at its hub end, as indicated at 2|,by forgingior the like,

a collar 22"being upset therein for connecting the blade to the hub in usual and well-known manner.

The diameter of the tube 20 is such that' when the tube is forged or otherwise formed to the iinished cross-sectional shape of the propeller blade,

25 terminating at a point spaced from the oppo- 'site end of the tube blank 2U, as shown in Fig. 1.

In some cases it may be desirable to reinforce I the edge portions', of the blade in which case smaller tubes 26 and 2l may be located within the tube blank '20 at opposite sides of the reinforcing tube 23 and the ends of these smaller tubes extending intov the tapered end portion of the tube blank 20 may be cut oi angularly, as indicated at 28, in order that they may be extended into the reduced tapered hub end portion of the blade.

The partly completed product, as shown in Figure 1, is then forged or pressed to 4substantially the desired cross-sectional shape of the iinished blade, assuming the shape shown in Fig. 2,

flattening the tube blank 20, and the reinforcing tubes 23,"26 and 2l to the various elliptical crosssectional shapes shown in Figs. 4 to 16, inclusive.

In order to produce the desired contour ofthe blade the surplus metal 'of the deformed tube blank 20, as shown in Fig. 2, is then sheared or trimmed off, along the broken line29 indicated on said figure, and the sheared edges are then Welded together, as at 29a, forming the finished blade shown in Fig.- 3.

The reinforcing tubes 21k,y 26 and 21 may be connected to the tube blank 20, as byresistance welding, as shown at 30, -3| and. 32,-respectively.

As shown in the cross-*sectional views, Figs. 4

to 16, inclusive, the hub end portion 2| of the p tube 20 remains circular while Vthe tube 20 from metal tube located sectional thickness ,of the hollow bladeand deformed to to the cross-sectional shape of the blade.

from the hub end toward the tip,

the point at which these .smaller tubes havlngthe cross-sectional shapes shown at the several stations between these points.

With this constructiomthe propeller blade is reinforced through its longitudinal center from the hub end almost to the tip by means of the central tube 25, which is deformed throughout its length to conform to the cross-sectional shape of the blade from hub totip, thus, strengthening aaeaics the section'vFig. 9 is taken, I

hub end pori-.ion of and of increasingly atter shape toward its other end to conform to the cross-sectional thickness of the blade, and smallthe blade throughout its length against the vibration caused by rapid rotation of the propeller when in use.

Furthermore, the edge portions of the blade are reinforced throughout a portion of its length by the small tubes 26 and 21 located-within the edge portions of the hollow blade and deformed I claim:

1. A hollow metal propeller having a substantially cylindric hub end portion and being of increasingly flatter elliptic cross-sectional 'shape y to conform to the cross-sectional shape thereof.

from the hub end toward the tip, a reinforcing 4 throughthe longitudinal cenr of the hollow blade and having a `cylindric end portion snugly fitting within the cylindric hub end portion of ,the blade and being of increasingly flatter elliptic cross-sectional shape toward its otherend -.to conform to the crossof the blade, and smaller reinforcing tubes locatedwithin the edge portions 2. A hollow metal propeller having a substantially cylindric hub end portion' and being of increasingly flatter elliptic cross-sectional shape a reinforcing metal tube located thro. h the longitudinal center 'of the hollow blade and having a cylindric end portion snugly 4tting within the -cylindric correspond x cylindric hub end portion,

vtions l tube being spaced inward from the edges of the i er reinforcing tubeslocated within the edge porhollow blade and deformed to correouter sheath and having a considerably greater radii than the corresponding. edge portions of.

the out'er sheath.

, 4. A hollow metal propeller comprisingan outer sheath of substantially ellipticvcross-sectional shape throughout the greater portion of its length and being of increasingly flatter elliptic crosssectional shape toward the tip end, and a reinforcing metal tube locatedA through the longitudinal center of the outer said tube being tapered and of increasingly flatter elliptic. cross-sectional shape toward the tip end of the blade, the sides of the tube being connected to the adjacent side portions of the outer sheath and the edges 0f the tube being spaced inward from the edges of the outer sheathrandhavin'g a considerably greater v 'radii than the corresponding edge portions of the outerv sheath.

the blade and being tapered elliptic cross-sectional propeller comprising an outr' increasingly flatter elliptic crosssheathland having a cHA'rRmrs H. BRAUcmEn. 

